m1n1/src/hv_wdt.c

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/* SPDX-License-Identifier: MIT */
#include "hv.h"
#include "adt.h"
#include "smp.h"
#include "uart.h"
#include "utils.h"
#define WDT_CPU 1
#define WDT_TIMEOUT 1
static bool hv_wdt_active = false;
static bool hv_wdt_enabled = false;
static volatile u64 hv_wdt_timestamp = 0;
static u64 hv_wdt_timeout = 0;
static volatile u64 hv_wdt_breadcrumbs;
static u64 cpu_dbg_base = 0;
void hv_wdt_bark(void)
{
u64 tmp = hv_wdt_breadcrumbs;
uart_puts("HV watchdog: bark!");
uart_printf("Breadcrumbs: ");
for (int i = 56; i >= 0; i -= 8) {
char c = (tmp >> i) & 0xff;
if (c)
uart_putchar(c);
}
uart_putchar('\n');
uart_puts("Attempting to enter proxy");
struct uartproxy_msg_start start = {
.reason = START_HV,
.code = HV_WDT_BARK,
};
uartproxy_run(&start);
reboot();
}
void hv_wdt_main(void)
{
while (hv_wdt_active) {
if (hv_wdt_enabled) {
sysop("dmb ish");
u64 timestamp = hv_wdt_timestamp;
sysop("isb");
u64 now = mrs(CNTPCT_EL0);
sysop("isb");
if ((now - timestamp) > hv_wdt_timeout)
hv_wdt_bark();
}
udelay(1000);
sysop("dmb ish");
}
}
void hv_wdt_pet(void)
{
hv_wdt_timestamp = mrs(CNTPCT_EL0);
sysop("dmb ish");
}
void hv_wdt_suspend(void)
{
hv_wdt_enabled = false;
sysop("dsb ish");
}
void hv_wdt_resume(void)
{
hv_wdt_pet();
hv_wdt_enabled = true;
sysop("dsb ish");
}
void hv_wdt_breadcrumb(char c)
{
u64 tmp = hv_wdt_breadcrumbs;
tmp <<= 8;
tmp |= c;
hv_wdt_breadcrumbs = tmp;
sysop("dmb ish");
}
void hv_wdt_init(void)
{
int node = adt_path_offset(adt, "/cpus/cpu0");
if (node < 0) {
printf("Error getting /cpus/cpu0 node\n");
return;
}
u64 reg[2];
if (ADT_GETPROP_ARRAY(adt, node, "cpu-uttdbg-reg", reg) < 0) {
printf("Error getting cpu-uttdbg-reg property\n");
return;
}
cpu_dbg_base = reg[0];
}
void hv_wdt_start(void)
{
hv_wdt_breadcrumbs = 0;
hv_wdt_timeout = mrs(CNTFRQ_EL0) * WDT_TIMEOUT;
hv_wdt_pet();
hv_wdt_active = true;
hv_wdt_enabled = true;
smp_call4(WDT_CPU, hv_wdt_main, 0, 0, 0, 0);
}
void hv_wdt_stop(void)
{
hv_wdt_active = false;
smp_wait(WDT_CPU);
}